Whant brand of Metformin causes the less amount of bloating?

I was taking a round flat pill (manufacturer unknown) from CVS but had to change pharmacy due to insurance. I am now taking a round fatter pill with a 12 on one side and an A on the other side from Kroger. I'm am now more bloated all of the time as opposed to occasionally with the other brand. would you happen to know which brand causes the least amount of bloating. Both pills were 500 mg twice a day. Also would a extended release version be better for bloating.